Sidewall construction for a tire



Dec. 23, 1958 B. J. RENAUD SIDEWALL CONSTRUCTION FOR A TIRE Filed May 9,1955 ATTORNEY.

nite States aten SIDEWALL CONSTRUCTION FOR A TIRE Bruce J. Renaud,Detroit, Mich., assignor to United States Rubber Company, New York, N.Y., a corporation of New Jersey Application May 9, 1955, Serial No.506,838

8 Claims. (Cl. 152353) This invention relates to vehicle tires of thetype incorporating for decorative purposes rubber stocks of twodifferent colors, usually black and white, in the sidewalls thereof.

In the manufacture of tires of this type, it is impossible to obtain asharp, even line of juncture between the two stocks merely by carefulfabrication, as in the subsequent molding and vulcanization there'is aninner-flow of the stocks resulting in an uneven, irregular line ofjuncture therebetween.

In order to obtain a sharp, even line of juncture, it has been thepractice to lap one of the stocks over the other at the joining edges,usually by the use of a separate cover strip, and after the molding andvulcanizing of the tire to grind or buff away the protruding portion ofthe overlapped stock to form an even regular, externally visible line ofjuncture between the stocks.

The primary object of the present invention is to provide a sidewallconstruction which will eliminate the necessity of using separate coverstrips or overlapping constructions and the subsequent grinding orbuffing operations inherent in the methods heretofore used, but which atthe same time will provide an even regular, boundary line between thetwo contrasting stocks.

To this end, the present invention contemplates the provision of a flapor lip formed of one of the stocks which extends or projects therefromin overhanging spaced relation to the adjacent edge of the other stockto conceal the irregular line of juncture between the two stocks.

In this manner, the externally visible boundary line be tween the twostocks is formed by the regular, even, molded free edge of the flap orlip. The irregular line of juncture between the two stocks beingconcealed, no grinding or bulfing subsequent to the molding of the tireis necessary. The contrast between the two stocks is enhanced by theshadow illusion and three dimensional effect created by the overlyingflap or lip.

The elimination of the grinding or bufling operation, in addition toproviding a considerable saving in labor, also eliminates the dulling ofthe surface of the tire as results when the surface is buffed or ground,and further minimizes sidewall checking which often is initiated bybuffing or grinding of the surface of the tire. As no surface stock isground away, there is no need for overlapping the two stocks and noseparate cover strip need be applied.

The provision of the flap or lip also provides generous tolerances inthe placement of the two stocks during fabrication, as the line ofjuncture between the two stocks may vary by an amount equal to the widthof the flap or lip and still be concealed by the flap or lip.

If the line of juncture between the two stocks is not completelyconcealed by the flap or lip, the unconcealed portion can easily becamouflaged with paint, since the trough formed by the flap preventsstreaking of the paint onto the colored sidewall. Furthermore, theraised portion of the sidewall or bufiing rib protects the paint and theflap from scuffing and scraping.

The lip or flap also minimizes dirt streaking of the lighter coloredstock, as the flap or lip forms a trough along which dirty water maydrain.

Other objects and advantages of the invention will become apparent fromthe following description when read in conjunction with the accompanyingdrawings wherein:

Fig. 1 is a fragmentary perspective view of a portion of a tireconstructed in accordance with the present invention showing the flap orrib which overlies and conceals the line of juncture between the twostocks in the sidewall thereof;

Fig. 2 is a partial sectional view through the sidewall of thefabricated tire prior to the molding and vulcanizing thereof showing theextra stock provided to form the bufiing rib and the flap or lip; and

Fig. 3 is a partial sectional view of the tire in the vulcanizing moldshowing the forming of the bufling rib and the flap or lip.

Referring to the drawings, and in particular to Fig. 1, in which thereis shown a section of a finished tire formed in accordance with thepresent invention, the uneven, irregular line of juncture 10 between therelatively dark rubber stock 11 forming the tread and outer sidewallportions, and the lighter colored stock 12 forming the inner sidewallportion is concealed by a circumferentially extending flap or lip 13which is formed of the lighter stock 12, protrudes from and overliesthe: juncture line 1! adjacent the usual buffing rib 14. As viewedexternally, the boundary line between the dark stock 11 and the lighterstock 12 appears as an even, regular, sharply defined line formed by theouter protruding, free edge 13a of the flap or lip 13. The constrastbetween the dark stock it and the lighter stock 12 is enhanced by theshadow illusion and third dimensional effect created by the flap or lip13.

Because the irregular line of juncture 1t! between the two stocks isconcealed by the flap or lip 13, no grinding or buffing is necessary andno overlapping cover strip is necessary. Should the juncture line bevisible because of improper location of the stocks thereof in thefabrication of the tire, the visible lighter stock along the line ofjuncture may be covered up with dark paint, without danger of the paintbeing scuffed or scraped off as the lip 13 in conjunction with thebuffing rib 14 will prevent such an occurrence.

As the rib or fiap 13 is not in contact with the darker stock 11, theneed for non-staining or barrier stock to prevent bleed through from thedark stock to the lighter stock is minimized. The trough formed by theflap or lip 13 minimizes dirt streaking of the lighter stock 12 bydraining off dirty water that might .run down the outer dark stock 11.

Preferably, the flap or lip 13 does not extend out from the surface ofthe tire any further than the outer surface of the rib 14, when the tireis mounted on a rim and inflated, so that the rib 14 will protect theflap or lip against damage by scufiing or scraping.

The tire of the invention is otherwise of conventional construction andincludes a fabric carcass 15 and bead wire bundles 16 to which thecarcass is anchored during vulcanization.

In fabricating the tire, an extra thickness 11a of the dark stock 13. isprovided adjacent the joining edge thereof for forming the bufiing rib14 and an extra thickness 12a of the lighter stock 12 is providedadjacent the joining edge thereof to form the flap or lip 13, as shownin Fig. 2. The tire is otherwise fabricated and shaped to approximatetire shape in the conventional manner.

After fabrication and shaping, the tire is placed in the tire mold 17,as illustrated in Fig. 3. During the molding and vulcanizing of thetire, the buffing rib 14 and the flap or lip 13 are formed. The buffingrib 14 is 3 formed by a recess 18 provided in the wall of the mold 17and the rib or flap 13 is formed by a recess 19 in the wall of the mold17 which extends towards the recess 18, at an angle of approximately 10to a line tangent to the outer surface of the rib.

From the above description, it can be seen that there is provided asidewall construction for a tire incorporating two stocks of diilerentcolors which provides an even, regular, sharply defined line ofdemarcation between the two difierent colored stocks without thenecessity of performing a buffing or grinding operation attcr the tirehas been molded and vulcanized, and which minimizes dirt streaking ofthe lighter stock, eliminates the necessity of a separate cover strip orthe use of non-staining or barrier stocks, and provides for a generoustolerance in the placement or positioning of the stocks in thefabrication of the tire. The term rubber has been used herein to denotenatural or synthetic rubbers or blends thereof.

Having thus described my invention, what I claim and desire to protectby Letters Patent is;

1. In a vehicle tire having a sidewall formed of at least two externallyvisible concentric bands of different colored rubber stocks, acircumferential external lip formed of one of said stocks extendingtherefrom in overhanging spaced relation to the line of juncture between the two bands of different colored rubber stocks, to substantiallyconceal the said line of juncture.

2. In a vehicle tire having a sidewall formed of at least two externallyvisible concentric bands of different colored rubber stocks, acircumferentially extending outwardly projecting external rib formed ofone of said stocks adjacent the line of juncture between said bands, anda lip formed of the other of said stocks and extending therefrom inoverhanging spaced relation to the line of juncture between the twobands, to substantially conceal the same.

3. In a vehicle tire having a sidewall formed of a radially outer bandof comparatively dark rubber stock and a radially inner band of lightercolored rubber stock, a circumferentially extending external lip formedof said lighter colored stock and projecting therefrom in over hangingspaced relation to the adjacent dark stock, and substantially concealingthe line of juncture between the two bands of the different coloredstocks.

4. In a vehicle tire having a sidewall formed of a radially outer bandof comparatively dark colored rubber stock and a radially inner band oflighter colored rubber stock, a circumferentially extending outwardlyprojecting external rib formed of the dark colored stock adjacent theline of juncture between the two bands, and a circumferentiallyextending external lip formed of the lighter colored rubber stock andprojecting therefrom in overhanging spaced relation to and substantiallyconcealing the line of juncture between the two stocks.

5. In a method of forming a tire having a sidewall formed of at leasttwo externally visible concentric bands of different colored rubberstocks, the step of forming during molding of the tire a circumferentiallip of one of said stocks extending in overhanging spaced relation tothe line of juncture between the stocks to substantially conceal thesame.

6. In a method of forming a tire having a sidewall formed of twoconcentric bands of different colored rubber stocks, the steps offorming a circumferentially extending outwardly projecting external ribfrom one of said stocks adjacent the line of juncture between thestocks, and forming a circumferentially extending lip from the other ofsaid stocks which projects therefrom in overhanging spaced relation tothe line of juncture between the two bands of stocks to substantiallyconceal the same.

7. In a method of forming a tire having a sidewall formed of a radiallyouter externally visible band of relatively dark rubber stock and aradially inner externally visible band of a lighter colored rubberstock, the step of forming a circumferential external lip of the lightercolored rubber stock projecting therefrom in overhanging spaced relationto the adjacent dark colored stock to substantially conceal the line ofjuncture between the two stocks.

8. In a method of forming a tire having a sidewall formed of a radiallyouter externally visible band of rubber stock of a relatively dark colorand a radially inner externally visible band of a lighter colored rubberstock, the steps of forming during melding of the tire acircumferentially extending outwardly projecting external rib of thedark colored stock adjacent the line of juncture between the stocks, andforming a circumferential external lip from the lighter stock extendingtherefrom in overhanging spaced relation to the line of juncture between the two stocks, for the purposes set forth.

References Cited in the file of this patent UNITED STATES PATENTS1,940,077 Co e Dec. 19, 1933 2,440,804 Lyon May 4, 1948 2,572,259Gottschall Oct. 23, 1951 2,685,904 Brandau Aug. 10, 1954 2,742,942 OwenApr. 24, 1956

